In practice, it is known to monitor industrial processes like labelling processes to get information about the consumption of consumable supplies like e.g. adhesive. The machine operator can adjust the amount of adhesive to be fed with such determined information so that a sufficient adhesive is used for the labelling process.
DE4137319 A1 discloses a method and a device for monitoring of a labeling machine to get information about the adhesive consumption. This is done by recording the number of items passing through the labeling machine as well as the amount of consumed adhesive during the same period of time. From the detected values, an adhesive consumption can be specified.
DE102008049830 A1 discloses a further method for the determination of adhesive consumption of a cold-adhesive labeling machine for labeling containers with labels, wherein the consumption of adhesive is determined by a measuring device during the labeling process continuously and a normalized adhesive consumption, i.e. the consumption of glue for a certain number of labels, is calculated using the processed data in a time interval labels and a surface Masses of the labels.
Both disclosures provide a possibility to monitor the adhesive consumption of the labelling machine to adjust the amount of fed adhesive.
EP1792663 A1 discloses a delivery device which can be used in an application system, for the processing of low temperature hot melt adhesive comprising a melt tank for the adhesive as well as heating elements and an auto feed device integrally connected to the tank. This delivery device is a closed system for automatically processing and application of an adhesive and can be used in an application system for the adhesive. It could also be used for an upgrade of older application systems. But the delivery device provides no possibility to monitor the amount of dispensed adhesive or to monitor any characteristics of the adhesive.
German Utility Model No. 296 20 763.2 describes an application system which consists of an adhesive reservoir, a feed pump and an applicator head comprising at least one applicator nozzle. The adhesive reservoir, the feed pump and the applicator head are connected by a pipe carrying the adhesive. At least one sensor for the adhesive volume flow rate between the feed pump and the at least one applicator nozzle is provided. The function of this sensor for the adhesive volume flow rate is to measure the volume of adhesive actually delivered by the feed pump to at least one applicator nozzle. If in the course of a work cycle the sensor should detect that not enough adhesive, if any, is being delivered, a corresponding monitoring circuit triggers an immediate interruption in production readily discernible to the machine attendant. The application system does not comprise a closed delivery device therefore any upgrade of the application system could be very expensive.